Blood vessel permeability-enhancement for the treatment of vascular diseases

ABSTRACT

This invention relates to methods of enhancing the permeability of blood vessels to therapeutic agents.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 13/079,239,filed on 4 Apr. 2011 which, in turn, is a continuation of applicationSer. No. 11/998,013, filed 27 Nov. 2007, both of which are incorporatedby references as if fully set forth herein.

FIELD

This application relates to the fields of chemistry, material science,medical devices and medicine. In particular it relates to a method ofmodulating the permeability of mammalian vessel membranes with regard tothe administration of therapeutic agents.

BACKGROUND

In general, therapeutic agents for the treatment of various diseases areadministered in one of two modalities: systemic or local. Systemicdelivery involves the administration of a therapeutic agent at adiscrete location remote from the afflicted locale, followed bydispersal of the agent throughout the patient's body including, ofcourse, to the target site or organ. In order to insure that atherapeutically effective amount of the agent reaches the afflictedsite, it is usually necessary to administer an initial dosesubstantially greater than the therapeutically effective amount toaccount for dilution the agent undergoes as it spreads throughout thebody and loss of agent due to reaction with bodily components such asenzymes. Systemic delivery is carried out primarily in two ways:introduction of the therapeutic agent into the digestive tract (enteraladministration) or into the vascular system (parenteral administration),either directly such as injection into a vein or an artery or indirectlysuch as injection into a muscle or into the bone marrow. Delivery byeach of these routes is strongly influenced by the so-called ADMETfactors: absorption, distribution, metabolism, excretion and toxicity.For enteric administration, such factors as a compound's solubility, itsstability in the acidic environs of the stomach and its ability topermeate the intestinal wall all affect the extent to which the drug isabsorbed and therefore its bioavailability. For parenteral deliveryfactors such as enzymatic degradation, the lipophilic/hydrophilicpartitioning coefficient, protein binding, etc. will affect thebioavailability of an agent.

Local delivery comprises administration of the therapeutic agent atleast proximally but preferably directly to the afflicted locale. TheADMET factors tend to be less important than with systemicadministration since the agent is being delivered essentially directlyto the treatment site. Thus, the initial dose can be at or very close tothe therapeutically effective amount. With time, some of the locallydelivered therapeutic agent may diffuse over a wider region but such isnot the intent of localized delivery and the concentration of thediffused agent will ordinarily be sub-therapeutic, i.e., too low to havea beneficial effect.

While diffusion of a therapeutic agent affects both systemic and localdelivery modalities, it is particularly troublesome with regard tolocalized delivery where the amount of therapeutic agent being deliveredis often as close to the minimum effective concentration as possible toavoid secondary problems such as toxicity and other undesirable sideeffects. With regard to vascular disorders, the therapeutic agent mustusually traverse the endothelium, a layer of cells that line theinterior surface of all blood vessels, and all or a portion of the mediaif the agent is administered within the lumen of the vessel. If theagent is administered exterior to the vessel then it must traverse theperiadventitia, adventitia, or a portion of the media to reach thetargeted site. The rate at which the therapeutic agent penetrates intoand ultimately traverses these tissue layers versus the rate at whichthe therapeutic agent is diffused away from the locale of interestdetermines how much of the agent must be administered in the firstplace.

What is needed with regard to the local treatment of vascular disordersis a method of increasing the rate of therapeutic agent traverse of theperiadventitia/aventitia/media/endothelium so that less of the agent islost during the treatment, thereby requiring less agent initially with aconcomitant reduction in potential side effects and possibly cost. Thecurrent invention provides such a method.

SUMMARY

Thus, an aspect of this invention is a method of treating a vasculardisease, comprising: providing a delivery device; advancing the deliverydevice to a locale of interest in a vessel of a patient; administering apermeability-enhancing composition to the locale of interest through thedelivery device; and, administering a therapeutic agent to the locale ofinterest through the delivery device either as a component of thepermeability-enhancing composition or concomitantly with but separatelyfrom the permeability-enhancing composition or subsequent toadministration of the permeability-enhancing composition.

In an aspect of this invention administering the permeability-enhancingcomposition comprises bathing the locale of interest with a solutionthat is hyperosmolar in relation to endothelial cells at the locale.

In an aspect of this invention, the hyperosmolar solution comprises asolute selected from the group consisting of a biocompatible salt, amonosaccharide, a disaccharide, a water miscible biocompatible organicsolvent, a water-soluble biocompatible small organic molecule, awater-soluble protein, a water-soluble peptide and a water-solublebiocompatible surfactant.

In an aspect of this invention, the solute comprises one or morecompounds selected from the group consisting of water-soluble glucose,mannose, fructose, sucrose, trehalose, biocompatible halides,biocompatible phosphates, ethylene diamine tetraacetic acid, taurocholicacid, benzalkonium chloride, capric acid, melittin or an amino acid.

In an aspect of this invention, administering the permeability-enhancingcomposition comprises using a composition that physicochemicallyinteracts with at least one component of endothelial cells orextracellular matrix.

In an aspect of this invention, the permeability-enhancing compositioncomprises a saponin, a semi-synthetic saponin, DS-1, DS-1(R), DS-2 orQH-957.

In an aspect of this invention, the permeability-enhancing compositioncomprises hyaluronidase, recombinant hyaluronidase or rHuPH2O.

In an aspect of this invention, the permeability-enhancing compositioncomprises ethanol, propylene glycol, glycerol, N-methyl pyrrolidone,dimethylsulfoxide, xylene, nitric oxide or a nitric oxide generator.

In an aspect of this invention, the method herein further comprises amechanical permeation enhancer.

In an aspect of this invention, the delivery device comprises acatheter.

In an aspect of this invention, the catheter is selected from the groupconsisting of a porous balloon catheter, a double-wall porous ballooncatheter, and infusion catheter and a needle injection catheter.

In an aspect of this invention, the delivery device comprises animplantable medical device.

In an aspect of this invention, the implantable medical device comprisesa stent.

In an aspect of this invention, the delivery device comprises anangioplasty balloon.

In an aspect of this invention, the delivery device comprises a hollowneedle.

In an aspect of this invention, the therapeutic agent comprises aparticulate carrier.

In an aspect of this invention, the particulate carrier comprises ananoparticle, a micelle, a worm micelle, a liposome or a polymerosome.

In an aspect of this invention, the nanoparticle, micelle, worm micelle,liposome or polymerosome further comprises the permeability-enhancingcomposition.

In an aspect of this invention, the permeability enhancing compositionindependently comprises a separate nanoparticle, micelle, worm micelle,liposome or polymerosome.

In an aspect of this invention, the nanoparticle, micelle, worm micelle,liposome or polymerosome comprises a targeting component disposed on itssurface and, further, the permeability-enhancing composition is likewisedisposed on its surface.

In an aspect of this invention, the locale of interest comprises a siteof an atherosclerotic lesion, a restenotic lesion, a suspectedvulnerable plaque, a vulnerable plaque or a peripheral arterial lesion.

DESCRIPTION

Use of the singular herein includes the plural and visa versa unlessexpressly stated to be otherwise. That is, “a” and “the” is to beconstrued as referring to one or more of whatever the word modifies. Asa non-limiting example, “a lubricious polymer” includes one suchpolymer, two polymers or, under the right circumstances, even morepolymers unless it is expressly stated or is unambiguously obvious fromthe context that such is not intended. Likewise, “a solvent” may referto a single solvent or a mixture of two or more solvents unless, again,it is expressly stated or obvious from the context that such is notintended.

As used herein, a “delivery device” refers to any manner of apparatusthat is used or that may be used to reach a locale of interest in avessel in a patient's body. The device may be transitory, that is, itmay be a device that is inserted into a patient's body for only so longas is necessary to administer a permeability-enhancing composition and atherapeutic agent to a patient or it may be an implantable medicaldevice intended to remain in a patient's body for longer than necessaryto deliver the two components of this method, possibly for as long asthe remaining lifetime of the patient. Intermediate between transitorydevices and implantable medical devices intended to remain in placepermanently are biodegradable implantable medical devices which overtime degrade to substances that can either be adsorbed into or excretedby the body.

An example of a transitory delivery device is, without limitation, assimple a device as a hollow needle that can be inserted into a patient'sbody at or near a locale of interest in a vessel and through which thecomponents of the method herein can be delivered. The needle may beinserted into the adventitia at the locale of interest or it may beinserted directly into the vascular lumen. An example, withoutlimitation, of a transitory device is a vascular catheter.

Another non-limiting example of a transitory delivery device is avascular catheter. A vascular catheter comprises a thin, flexible tubewith a manipulating means at one end, referred to as the proximal end,which remains outside the patient's body, and an operative device at ornear the other end, called the distal end, which is inserted into apatient's artery or vein. The catheter is often introduced into apatient's vasculature at a point remote from the locale of interest,e.g., into the femoral artery of the leg where the target is the heart.The catheter is steered, assisted by a guide wire than extends through alumen in the flexible tube, to the target site whereupon the guide wireis withdrawn at which time the lumen may be used for the introduction oftherapeutic agents to the locale of interest.

An “implantable medical device” refers to any type of appliance that istotally or partly introduced, surgically or medically, into a patient'sbody or by medical intervention into a natural orifice, and which isintended to remain there after the procedure. As noted above, theduration of implantation may be essentially permanent, i.e., intended toremain in place for the remaining lifespan of the patient; until thedevice biodegrades; or until it is physically removed.

Examples of implantable medical devices include, without limitation,implantable cardiac pacemakers and defibrillators; leads and electrodesfor the preceding; implantable organ stimulators such as nerve, bladder,sphincter and diaphragm stimulators, cochlear implants; prostheses,grafts, stent-grafts, artificial heart valves and cerebrospinal fluidshunts.

Further non-limiting examples of implantable medical devices are vesselwraps and stents. A vessel wrap is a thin sheet of flexible material,which may be fabric, polymer, metal, etc. that is literally wrappedaround the outside of a vessel and is in contact with the outer surface.The wrap may be solid or it may be formed in virtually any manner ofdesired pattern such as, without limitation, a mesh, a ribbed polymericstructure or an embossed metal sheet.

A “stent” refers generally to any device used to hold tissue in place ina patient's body. Particularly useful stents, however, are those usedfor the maintenance of the patency of a vessel in a patient's body whenthe vessel is narrowed or closed due to diseases including, withoutlimitation, tumors (in, for example, bile ducts, the esophagus, thetrachea/bronchi, etc.), benign pancreatic disease, coronary arterydisease, carotid artery disease and peripheral arterial disease such asatherosclerosis, restenosis and vulnerable plaque. A stent can be usedin, without limitation, neuro, carotid, coronary, pulmonary, aorta,renal, biliary, iliac, femoral and popliteal arteries as well as otherperipheral vasculatures. A stent can be used in the treatment orprevention of diseases such as, without limitation, thrombosis,restenosis, hemorrhage, vascular dissection or perforation, vascularaneurysm, chronic total occlusion, claudication, anastomoticproliferation, bile duct obstruction and ureter obstruction.

In addition to the above uses, stents, including in particular those ofthis invention, may be employed for the delivery of therapeutic agentsto specific treatment sites in a patient's body. In fact, therapeuticagent delivery may be the sole purpose of the stent or the stent may beprimarily intended for another use such as those discussed above withdrug delivery providing an ancillary benefit. Any stent design currentlyknown or any that may be disclosed in the future that is directed atleast in part to the delivery of therapeutic agents to locales ofinterest in a patient's body are within the scope of this invention.

As used herein, a “locale of interest” refers to a location withinvessel of a patient that is the site of an atherosclerotic lesion or alocation in the vessel where an atherosclerotic lesion may occur, arestenotic lesion or a location in the vessel where a restenotic lesionmay occur, a known or suspected site of vulnerable plaque or a locationin a peripheral vessel where a peripheral arterial disease hasmanifested itself.

As used herein, a “vessel of a patient” refers to any of the essentiallytubular organ that transports blood in the mammalian body includingarteries, arterioles, veins, venules and capillaries. Preferably atpresent the vessel of a patient refers to an artery.

A “patient” refers to any species that might benefit from treatmentusing the method herein but at present is preferably a mammal and mostpreferably a human being.

As used herein, “administering a permeability-enhancing composition” toa locale of interest refers to contacting the composition with theendothelium at the locale of interest if the delivery device is situatedwithin the lumen of a vessel or with the periadventitia or adventitia ifthe delivery device is situated outside the vessel adjacent to a localeof interest situated within the vessel. The permeability-enhancingcomposition must be in contact with the endothelium, media, adventitiaor (peri)adventitia for a sufficient duration such that the compositionhas time to have its intended effect, that is, to increase thepermeability of the tissue at that locale.

While it is understood that the method of this invention is applicableto either the endothelium, media, the periadventitia or the adventitia,it is presently preferred that it be applied to permeability enhancementof endothelial tissue. Thus the remainder of this disclosure will bedirected to the endothelium but it is understood that essentially thesame technique will apply to the outer tissues of blood vessels as well.

If the permeability-enhancing composition is intended to increasepermeability by creating a hyperosmolar or hypertonic (q.v, below)environment at the locale of interest, the composition may beadministered by simply suffusing the locale for a period of time beforeintroducing a therapeutic agent to the site. If on the other hand, thecomposition is one that reacts with the constituents of the endothelialcells themselves or the constituents of the extracellular matrix (EM),then the composition may be administered much the same way as thetherapeutic agent. That is, a previously determined effective amount ofthe composition is administered to the locale of interest either priorto or concomitant with administration of the therapeutic agent.

As used herein, “bathing” the locale of interest refers to supplying asufficient amount of the hyperosmolar solution to the locale of interestso as to maintain the osmotic imbalance at the site for a sufficientduration for the efflux of water from the cells to take place to anextent sufficient to render the region between the cells, i.e., theregion of the EM more penetrable to the therapeutic agent or particulatecarrier administered concurrent with or subsequent to the bathing step.Since blood is constantly flowing through the vasculature this mayrequire a constant stream of the hyperosmolar solution directed to theendothelium at the locale of interest so as to create the osmoticimbalance. It may be beneficial to temporarily block the vessel eitherproximal to the locale of interest (as determined from the direction ofblood flow, the side closest to the heart being proximal) or bothproximal and distal to the locale of interest, in this latter casethereby creating a compartment that can be flooded with the hyperosmolarsolution. In this latter instance a bolus of the hyperosmolar may beadministered.

As used herein, “administering a therapeutic agent to the locale ofinterest” refers to contacting a therapeutically effective amount of thetherapeutic agent or particulate carrier containing the therapeuticagent with the endothelium. While it may be possible to contact thetherapeutic agent with the periadventitia, adventitia, or media and haveit traverse the additional tissue to reach the endothelium, at presentit is preferred that the therapeutic agent be administered from insidethe vessel, i.e., through the lumen of the vessel, such that it can beplaced in immediate intimate contact with the endothelium. A“therapeutically effective amount” refers to that quantity of thetherapeutic agent that has a therapeutic beneficial effect on the healthand well-being of the patient. A therapeutic beneficial effect on thehealth and well-being of a patient includes, but it not limited to: (1)curing the disease; (2) slowing the progress of the disease; (3) causingthe disease to retrogress; or, (4) alleviating one or more symptoms ofthe disease. As used herein, a therapeutically effective amount includesa prophylactically effective amount, which is that amount of thetherapeutic agent that has a prophylactic beneficial effect on thehealth and well-being of the patient. A prophylactic beneficial effecton the health and well-being of a patient includes, but is not limitedto: (1) preventing or delaying on-set of the disease in the first place;(2) maintaining a disease at a retrogressed level once such level hasbeen achieved by a therapeutically effective amount of a substance,which may be the same as or different from the substance used in aprophylactically effective amount; or, (3) preventing or delayingrecurrence of the disease after a course of treatment with atherapeutically effective amount of a substance, which may be the sameas or different from the substance used in a prophylactically effectiveamount, has concluded.

As used herein, “permeability” refers to the degree to which atherapeutic agent or particulate carrier containing a therapeutic agentis able to traverse the endothelial layer and gain access to thesub-structure within.

“Permeability-enhancing,” as the term itself suggests, refers to theability of a composition to increase the ease with which the therapeuticagent or particulate carrier crosses the endothelium as measured by thepercentage of an administered amount that is found on the side ofendothelium away from the lumen, either totally or per unit time.

As used herein, a “permeability-enhancing composition” refers to one ormore substances, which may be neat or in solution, which alone or incombination are capable of increasing the permeability of theendothelium of a blood vessel. For the purposes of this invention, being“capable of increasing the permeability of the endothelium” may be assimple as increasing the solute concentration outside the endothelialcells such that a osmotic imbalance is created resulting in watereffluxing out of the cells thereby causing the cells to collapse or itmay mean actually reacting with a constituent of the endothelial cellsor the EM.

For the purposes of this invention, permeability of the endothelium canbe increased by two mechanisms. One mechanism involves creating ahyperosmotic, hyperosmolar or hypertonic (the terms are interchangeable)environment at the locale of interest. In a hyperosmotic environment,the solute concentration outside a cell is higher than the soluteconcentration within the cell resulting in the creation of an osmoticimbalance. Due to this imbalance there will be a net flow of water fromthe lower concentration environment to the higher concentrationenvironment as the system naturally attempts to reestablish an isotoniccondition where there is no net flow of water into or out of the cells.In the hyperosmotic environment created by an embodiment of thisinvention, water flows out of the cells causing the cells to at leastpartially collapse, preferably not to the point of permanently damagingthe cells, thereby increasing the distance between cells and stretching,at some points perhaps even pulling apart, the EM. Therapeutic agentsadministered to the locale of interest will then be able to more easilyfilter between the endothelial cells and access the region beyondwherein lies the actual target of the therapeutic agent.

The second means of increasing the permeability of the endotheliuminvolves physicochemical interaction between the composition andcomponents of the endothelial cells themselves or between thecomposition and components of the EM. An example, without limitation, ofa composition that interacts with endothelial cell components is thesaponins.

Saponins are glycosides of plant origin. They contain either a steroid,alkaloid steroid or triterpenoid aglycone to which one or more sugarchains are attached. The sugars are usually glucose, galactose,glucuronic acid, xylose or rhamnose although others are known to occurin certain saponins. The saponins directly affect cell permeability byreversibly interacting with the outer cell membrane including formingpores therein. It has been reported that it is the number of sugar sidechains on a given saponin that most influences itspermeability-enhancing capabilities although contradictory reports alsoexist. The different conclusions may be the result of the particulartype of cell used in the study. Since the actual mode of action is notpertinent to this invention, without being bound to any particulartheory it appears that the permeability enhancing capabilities ofsaponins may be related to a combination of target membrane composition,the type of saponin side chain(s) and the nature of the aglycone. In anyevent, those skilled in the art will be able, based on this disclosure,to select appropriate saponins for use in the method of this invention.

Of the myriad known saponins, presently preferred for the purposes ofthis invention are saponins extracted from Quillaja saponaria, a memberof the Rosaceae family. The Quillaja saponins consist of a triterpenewith sugar side chains on carbons 2 and 28. Variation in the sugar sidechain give rise to at least 50 different types of Quillaja saponins.

In addition to the naturally-occurring Quillaja saponins, semi-syntheticderivatives can also be used in the methods of this invention. As shouldbe obvious given the diversity of structure in the saponins themselves,the number of possible structures of semi-synthetic saponins is legionand all such compounds are within the scope of this invention. Inparticular, however, the semi-synthetic saponins known as DS-1, DS-1(R),DS-2 and QH-957 are presently preferred for use in the methods of thisinvention. DS-1 and DS-2 are the result of mild alkaline hydrolysis ofacyl groups on the saponin. DS-1 and DS-2 are more hydrophilic than theparent compound. Reduction of an aldehyde group of DS-1 affords DS-1(R).Removal of the fucose-containing oligosaccharide of DS-1 gives QH-957.

An example of a composition that reacts with components of the EM ratherthan components of the endothelial cells themselves is hyaluronidase.The EM is composed of an interlocking mesh of fibrous proteins andglycosaminoglycans (GAGs). GAGs are carbohydrate polymers that attachthemselves to the fibrous proteins of the EM to form proteoglycans.Among the proteoglycans involved in EM formation are heparin sulfate,chondroitin sulfate and keratan sulfate. The EM also containsnon-proteoglycan components, in particular hyaluronic acid orhyaluronan. Hyaluronan is a non-sulfonated polysaccharide GAG consistingof alternating residues of D-glucouronic acid and N-acetylglucosamine.It is widely distributed throughout connective, endothelial and neuraltissues. Hyaluronan is one of the chief components of the EM, in fact itas been estimated that a 150 lb human has roughly 15 grams of hyaluronanin his/her body.

Hyaluronidase is an enzyme that hydrolyzes hyaluronan, by cleaving theglucosaminidic bond between C1 of the acetylglucosamine and the C4 ofglucouronic acid, the two constituents of hyaluronic acid. This resultsin a temporary decrease in the viscosity of the EM which facilitates themovement of transudates and exudates such as therapeutic agents past theendothelial layer.

Naturally-occurring hyaluronidases constitute a group of neutral or acidactive enzymes that occur throughout the animal kingdom and that varywith respect to substrate specificity and mechanisms of action. Ofprimary import to this invention are the mammalian hyaluronidases (EC3.2.1.35), which are endo-β-N-acetylhexoaminidases that affordtetrasaccharides and hexasaccharides as the major end products ofhydrolysis. The hyaluronidases have both hydrolytic and transglycosidaseactivity and can degrade hyaluronan and chrondroitin sulfates, anotherconstituent of the EM.

In addition to naturally-occurring hyaluronidase, recombinanthyaluronidases that maintain the ability to cleave hyaluronan, be it bythe same mechanism or a different one, are also within the contemplationof this invention. “Recombinant” simply means that the hyaluronidaseso-designated is created (expressed) by an artificial gene, one thatdoes not occur in nature. Presently preferred is a recombinant humanhyaluronidase known as rHuPH2O, available from Halozyme Theraputics,Inc., San Diego, Calif. PH-20 is a widely conserved mammalianglycosylphosphatidyl-inositol-anchored spermatozoa surface proteinwell-known for its hyalouronidase activity. Native human hyaluronidaseHuPH2O, is reported to be a 509 residue protein, a truncated version(residues 36-482, inclusive) of which constitutes the recombinant form,rHuPH2O.

As used herein, a “therapeutic agent” refers to, without limitation, ananti-restenosis agent, an antiproliferative agent, an anti-inflammatoryagent, an antineoplastic, an antimitotic, an antiplatelet, ananticoagulant, an antifibrin, an antithrombin, a cytostatic agent, anantibiotic, an anti-allergic agent, an anti-enzymatic agent, anangiogenic agent, a cyto-protective agent, a cardioprotective agent, aproliferative agent, an ABC A1 agonist, an antioxidant, or anycombination thereof.

Examples of antiproliferative agents include, without limitation,actinomycins, taxol, docetaxel, paclitaxel, rapamycin,40-O-(3-hydroxy)propyl-rapamycin,40-O-[2-(2-hydroxy)ethoxy]ethyl-rapamycin, or 40-O-tetrazole-rapamycin,40-epi-(N1-tetrazolyl)-rapamycin, everolimus, Biolimus A9 (BiosensorsInternational, Singapore), deforolimus, AP23572 (Ariad Pharmaceuticals),perfenidone and derivatives, analogs, prodrugs, co-drugs andcombinations of any of the foregoing.

Examples of anti-inflammatory agents include both steroidal andnon-steroidal (NSAID) anti-inflammatory agents such as, withoutlimitation, clobetasol, alclofenac, alclometasone dipropionate,algestone acetonide, alpha amylase, amcinafal, amcinafide, amfenacsodium, amiprilose hydrochloride, anakinra, anirolac, anitrazafen,apazone, balsalazide disodium, bendazac, benoxaprofen, benzydaminehydrochloride, bromelains, broperamole, budesonide, carprofen,cicloprofen, cintazone, cliprofen, clobetasol propionate, clobetasonebutyrate, clopirac, cloticasone propionate, cormethasone acetate,cortodoxone, deflazacort, desonide, desoximetasone, dexamethasone,dexamethasone dipropionate, dexamethasone acetate, dexmethasonephosphate, momentasone, cortisone, cortisone acetate, hydrocortisone,prednisone, prednisone acetate, betamethasone, betamethasone acetate,diclofenac potassium, diclofenac sodium, diflorasone diacetate,diflumidone sodium, diflunisal, difluprednate, diftalone, dimethylsulfoxide, drocinonide, endrysone, enlimomab, enolicam sodium,epirizole, etodolac, etofenamate, felbinac, fenamole, fenbufen,fenclofenac, fenclorac, fendosal, fenpipalone, fentiazac, flazalone,fluazacort, flufenamic acid, flumizole, flunisolide acetate, flunixin,flunixin meglumine, fluocortin butyl, fluorometholone acetate,fluquazone, flurbiprofen, fluretofen, fluticasone propionate,furaprofen, furobufen, halcinonide, halobetasol propionate, halopredoneacetate, ibufenac, ibuprofen, ibuprofen aluminum, ibuprofen piconol,ilonidap, indomethacin, indomethacin sodium, indoprofen, indoxole,intrazole, isoflupredone acetate, isoxepac, isoxicam, ketoprofen,lofemizole hydrochloride, lomoxicam, loteprednol etabonate,meclofenamate sodium, meclofenamic acid, meclorisone dibutyrate,mefenamic acid, mesalamine, meseclazone, methylprednisolone suleptanate,momiflumate, nabumetone, naproxen, naproxen sodium, naproxol, nimazone,olsalazine sodium, orgotein, orpanoxin, oxaprozin, oxyphenbutazone,paranyline hydrochloride, pentosan polysulfate sodium, phenbutazonesodium glycerate, pirfenidone, piroxicam, piroxicam cinnamate, piroxicamolamine, pirprofen, prednazate, prifelone, prodolic acid, proquazone,proxazole, proxazole citrate, rimexolone, romazarit, salcolex,salnacedin, salsalate, sanguinarium chloride, seclazone, sermetacin,sudoxicam, sulindac, suprofen, talmetacin, talniflumate, talosalate,tebufelone, tenidap, tenidap sodium, tenoxicam, tesicam, tesimide,tetrydamine, tiopinac, tixocortol pivalate, tolmetin, tolmetin sodium,triclonide, triflumidate, zidometacin, zomepirac sodium, aspirin(acetylsalicylic acid), salicylic acid, corticosteroids,glucocorticoids, tacrolimus, pimecrolimus and derivatives, analogs,prodrugs, co-drugs and combinations of any of the foregoing.

Examples of antineoplastics and antimitotics include, withoutlimitation, paclitaxel, docetaxel, methotrexate, azathioprine,vincristine, vinblastine, fluorouracil, doxorubicin hydrochloride, andmitomycin.

Examples of antiplatelet, anticoagulant, antifibrin, and antithrombindrugs include, without limitation, sodium heparin, low molecular weightheparins, heparinoids, hirudin, argatroban, forskolin, vapiprost,prostacyclin, prostacyclin dextran, D-phe-pro-arg-chloromethylketone,dipyridamole, glycoprotein IIb/IIIa platelet membrane receptorantagonist antibody, recombinant hirudin and thrombin, thrombininhibitors such as Angiomax ä, calcium channel blockers such asnifedipine, colchicine, fish oil (omega 3-fatty acid), histamineantagonists, lovastatin, monoclonal antibodies such as those specificfor Platelet-Derived Growth Factor (PDGF) receptors, nitroprusside,phosphodiesterase inhibitors, prostaglandin inhibitors, suramin,serotonin blockers, steroids, thioprotease inhibitors,triazolopyrimidine, nitric oxide or nitric oxide donors, super oxidedismutases, super oxide dismutase mimetic,4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4-amino-TEMPO) andderivatives, analogs, prodrugs, codrugs and combinations thereof.

Examples of cytostatic or antiproliferative agents include, withoutlimitation, angiopeptin, angiotensin converting enzyme inhibitors suchas captopril, cilazapril or lisinopril, calcium channel blockers such asnifedipine; colchicine, fibroblast growth factor (FGF) antagonists; fishoil (ω-3-fatty acid); histamine antagonists; lovastatin, monoclonalantibodies such as, without limitation, those specific forPlatelet-Derived Growth Factor (PDGF) receptors; nitroprusside,phosphodiesterase inhibitors, prostaglandin inhibitors, suramin,serotonin blockers, steroids, thioprotease inhibitors,triazolopyrimidine (a PDGF antagonist) and nitric oxide.

Examples of antiallergic agents include, without limitation, permirolastpotassium.

Other compounds that may be used as bioactive agents of this inventioninclude, without limitation, alpha-interferon, genetically engineeredendothelial cells, dexamethasone, antisense molecules which bind tocomplementary DNA to inhibit transcription, and ribozymes, antibodies,receptor ligands, enzymes, adhesion peptides, blood clotting factors,inhibitors or clot dissolving agents such as streptokinase and tissueplasminogen activator, antigens for immunization, hormones and growthfactors, oligonucleotides such as antisense oligonucleotides andribozymes and retroviral vectors for use in gene therapy; antiviralagents; analgesics and analgesic combinations; anorexics;antihelmintics; antiarthritics, antiasthmatic agents; anticonvulsants;antidepressants; antidiuretic agents; antidiarrheals; antihistamines;antimigrain preparations; antinauseants; antiparkinsonism drugs;antipruritics; antipsychotics; antipyretics; antispasmodics;anticholinergics; sympathomimetics; xanthine derivatives; cardiovascularpreparations including calcium channel blockers and beta-blockers suchas pindolol and antiarrhythmics; antihypertensives; diuretics;vasodilators including general coronary; peripheral and cerebral;central nervous system stimulants; cough and cold preparations,including decongestants; hypnotics; immunosuppressives; musclerelaxants; parasympatholytics; psychostimulants; sedatives;tranquilizers; naturally derived or genetically engineered lipoproteins;and derivatives, analogs, prodrugs, codrugs and combinations of any ofthe foregoing.

Other bioactive agents include a corticosteroid, everolimus,zotarolimus, sirolimus, and derivatives thereof, paclitaxel, biolimusA9, a bisphosphonate, ApoA1, a mutated ApoA1, ApoA1 milano, an ApoA1mimetic peptide, an ABC A1 agonist, an anti-inflammatory agent, ananti-proliferative agent, an anti-angiogenic agent, a matrixmetalloproteinase inhibitor and a tissue inhibitor of metalloproteinase.

As used herein, “biocompatible” refers to a substance that, both in itsnative pure state and as any decomposition products that might begenerated from it, is not, or at least is minimally, toxic to livingtissue; does not, or at least minimally and reparably, injure(s) livingtissue; and/or does not, or at least minimally and/or controllably,cause(s) an immunological reaction in living tissue. With regard tosalts, both the cation and anion must be biocompatible. Examples ofgenerally biocompatible cations are, without limitation, sodium (Na⁺),potassium (K⁺), calcium (Ca⁺), magnesium (Mg⁺⁺), iron (Fe⁺⁺⁺) andammonium (NH₄ ⁺). Others are well-known to those skilled in the art.

As used herein, “water-miscible” refers to an organic liquid thatcombines with water to form a clear, homogenous mixture at theconcentrations required for the purposes of this invention. That amountwill be easily determinable by those skilled in the art based on thedisclosures herein with regard to the teaching that the desired resultis a hyperosmotic environment in the vicinity of the endothelium.

As used herein, “water-soluble” refers to a solid, which may beinorganic or organic, that forms a clear, homogenous mixture when placein water at the concentrations required for the purposes of thisinvention.

“Homogenous” merely means that the resultant mixture is sufficientlyuniform that a sample taken from any point in the mixture has the samecomposition as a sample taken from any other point in the mixture.

As used herein, an “amino acid” refers to any organic acid, i.e., amolecule with a —COOH functional group also containing an α-amino (—NH₂)group; however at present it is preferred that the amino acids beselected from the group commonly known as the standard amino acids orsometimes the proteinogenic amino acids because they are encoded by thenormal genetic code. There currently are 20 standard amino acids:alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid,glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine,phenyl alanine, proline, serine, threonine, tryptophan, tyrosine andvaline. Relatively recently selenoadenine has been found to beincorporated into a number of proteins and is included with the above asa useful amino acid for the purposes of this invention. Innaturally-occurring biological proteins, these amino acids existprimarily as l-enantiomers but for the purposes of this invention theymay be used as their l- or d-enantiomers or as racemic mixtures.

As used herein a “peptide” refers a short polymer formed by the linkingtogether of α-amino acids through the formation of amide bonds,sometimes referred to as peptide bonds. A protein, on the other hand,refers to a substantially longer polymer comprised of poly(peptides).There is no exact dividing line between a peptide and a protein and suchis not essential to this invention. Therefore, for the purposes of thisinvention a peptide refers to a poly(amino acid) of up to 50 amino acidswhile above 50 amino acids the compound will be considered a protein.

As used herein, a “surfactant” refers to an amphiphilic (having bothhydrophobic groups (their “tails”) and hydrophilic groups (their“heads”)) organic molecule that is soluble both in organic solvents andin water. They operate by reducing the surface tension between twomaterials, which may be liquid-gas, liquid-liquid or liquid-solid. Forthe purposes of the method of this invention their primary purpose iscreating a hyperosmotic environment in the vicinity of the endotheliumand secondarily to further ease the transfer of therapeutic agents orparticulate carriers through the endothelium by reducing surfacetensions between the agent/particle and the components of the EM.

As used herein, “physiochemically interacting” refers to the situationwhere a permeability-enhancing composition actually reacts with andchanges a component of the EM or an endothelial cell as opposed to thesituation where the composition merely creates a hyperosmolar conditionin the vicinity of the endothelium at the locale of interest. Examplesof such physicochemical interactions are described above with regard tosaponins (physiochemically interact with endothelial cell outermembrane) and rHuPH2O (physiochemically interact with hyaluronan). Othersuch permeability-enhancing compositions useful in the method hereinwill become apparent to those skilled in the art based on the disclosureherein and are within the scope of this invention.

As used herein, a “vascular disease” refers to a disease of the bloodvessels, primarily arteries and veins, which transport blood to and fromthe heart, brain and peripheral organs such as, without limitation, thearms, legs, kidneys and liver. In particular “vascular disease” refersto the coronary arterial system, the carotid arterial system and theperipheral arterial system. The disease that may be treated is any thatis amenable to treatment with a therapeutic agent, either as the soletreatment protocol or as an adjunct to other procedures such as surgicalintervention. The disease may be, without limitation, atherosclerosis,vulnerable plaque, restenosis or peripheral arterial disease.

“Atherosclerosis” or an “atherosclerotic lesion” refers to thedepositing of fatty substances, cholesterol, cellular waste products,calcium and fibrin on the inner lining or intima of an artery. Smoothmuscle cell proliferation and lipid accumulation accompany thedeposition process. In addition, inflammatory substances that tend tomigrate to atherosclerotic regions of an artery are thought toexacerbate the condition. The result of the accumulation of substanceson the intima is the formation of fibrous (atheromatous) plaques thatocclude the lumen of the artery, a process called stenosis. When thestenosis becomes severe enough, the blood supply to the organ suppliedby the particular artery is depleted resulting is strokes, if theafflicted artery is a carotid artery, heart attack if the artery is acoronary artery or loss of organ function if the artery is peripheral.

“Restenosis” or a “restenotic lesion” refers to the re-narrowing orblockage of an artery at or near the where angioplasty or other surgicalprocedure was previously performed to remove a stenosis. It is usuallydue to smooth muscle cell proliferation at times accompanied bythrombosis. Prior to the advent of implantable stents to maintain thepatency of vessels opened by angioplasty, restenosis occurred in 40-50%of patients within 3 to 6 months of undergoing the procedure.Post-angioplasty restenosis before stents was due primarily toneointimal hyperplasia and vasospasm, with smaller rates of dissectionand thrombosis or blood-clotting at the site of the procedure. Stentplacement essentially eliminates vasospasm and dissections. However, thestented sites are still susceptible to restenosis due to neointimalhyperplasia and abnormal tissue growth at the site of implantation.While the use of IIb-IIIa anti-platelet drugs such as abciximab andepifabatide, which are anti-thrombotic, reduced the occurrence ofpost-procedure clotting with stents (although stent placement itself caninitiate thrombosis. Restenosis tends also to occur at 3 to 6 monthsafter stent placement, but it is not reduced by the use of anti-clottingdrugs. Thus, alternative therapies are continuously being sought tomitigate, preferably eliminate, this type of restenosis. Drug elutingstents (DES) which release a variety of therapeutic agents at the siteof stent placement have been in use for some time and it is to improveddrug-delivery of DESs that this invention is at least in part directed.

“Vulnerable plaque” refers to an atheromatous plaque that has thepotential of causing a thrombotic event and is usually characterized bya very thin wall separating a lipid filled, necrotic core from the lumenof an artery. The thinness of the wall renders the plaque susceptible torupture. When the plaque ruptures, the inner core of lipid-rich plaqueis exposed to blood where it has the potential of causing a fatalthrombotic event through adhesion and activation of platelets and plasmaproteins to components of the exposed plaque.

The phenomenon of “vulnerable plaque” has created new challenges inrecent years for the treatment of heart disease. Unlike occlusiveplaques that impede blood flow, vulnerable plaque develops within thearterial walls, but it often does so without the characteristicsubstantial narrowing of the arterial lumen which produces symptoms. Assuch, conventional methods for detecting heart disease, such as anangiogram, may not detect the presence of vulnerable plaque in thearterial wall. After death, an autopsy can reveal the ruptured plaque inthe arterial wall. However, the pre-rupture narrowing of these plaquescannot typically be seen with commonly available medical imaging. Thus,for the purposes of this invention, it may be beneficial to treat alocale of interest where a vulnerable plaque is suspected to be presentbased on the symptomology at the locale even though the plaque has notbeen expressly observed.

The intrinsic histological features that may characterize a vulnerableplaque include increased lipid content, increased macrophage, foam celland T lymphocyte content, and reduced collagen and smooth muscle cell(SMC) content. This fibroatheroma type of vulnerable plaque is oftenreferred to as “soft,” having a large lipid pool of lipoproteinssurrounded by a fibrous cap. The fibrous cap contains mostly collagen,whose reduced concentration combined with macrophage derived enzymaticdegradation can cause the fibrous cap of these lesions to rupture underunpredictable circumstances. When ruptured, the lipid core contents,thought to include tissue factor, contact the arterial bloodstream,causing a blood clot to form that can completely block the arteryresulting in an acute coronary syndrome (ACS) event. This type ofatherosclerosis is coined “vulnerable” because of unpredictable tendencyof the plaque to rupture. It is thought that hemodynamic and cardiacforces, which yield circumferential stress, shear stress, and flexionstress, may cause disruption of a fibroatheroma type of vulnerableplaque. These forces may rise as the result of simple movements, such asgetting out of bed in the morning, in addition to in vivo forces relatedto blood flow and the beating of the heart. It is thought that plaquevulnerability in fibroatheroma types is determined primarily by factorswhich include: (1) size and consistency of the lipid core; (2) thicknessof the fibrous cap covering the lipid core; and (3) inflammation andrepair within the fibrous cap.

Peripheral vascular diseases are generally caused by structural changesin blood vessels caused by such conditions as inflammation,hyperlipidemia, diabetes, and tissue damage. A subset of peripheralvascular disease is peripheral artery disease (PAD) or equivalentlyherein a peripheral arterial lesion. PAD is a condition that is similarto carotid and coronary artery disease in that it is caused by thebuildup of fatty deposits on the lining or intima of the artery walls.Just as blockage of the carotid artery restricts blood flow to the brainand blockage of the coronary artery restricts blood flow to the heart,blockage of the peripheral arteries can lead to restricted blood flow tothe kidneys, stomach, arms, legs and feet.

As used herein, “late stent thrombosis” refers to the formation of bloodclots in the vicinity of an implanted stent long after—months, evenyears—the stent was in place. It has been hypothesized that theformation of blood clots may be due to delayed healing resulting fromthe use of cytostatic drugs.

As used herein “hollow needle” simply refers generally to the well-knownthin, elongate, tubular device having a tapered point that is used toinject therapeutic agents into various parts of the body includingwithout limitation subcutaneously although the shape of the needleitself for the purposes of this invention may be configured in ways thatare not usually seen with regard to syringes. Such alternateconfigurations are well-known to those skilled in the art.

As used herein, a “particulate carrier” refers to a biocompatible,generally non-therapeutic substance within which a therapeutic agentand/or a permeability-enhancing composition can be encapsulated or tothe surface of which either or both may be adhered. Examples ofparticulate carriers useful for the purposes of this invention are,without limitation, nanoparticles, micelles, worm micelles, liposomesand polymersomes.

As used herein, a “nanoparticle” refers to a solid particle having asits largest trans-sectional, i.e., as measured through the particle asopposed to along its surface, dimension of no greater than 500nanometers, preferably 250 nanometers and most preferably at present nogreater than 200 nanometers. The solid can have an desired shapealthough substantially spherical particles are well-known in the art,are readily prepared and are presently preferred. By “substantiallyspherical” is meant that the particles need not have a surface thatmimics a table tennis ball, i.e., virtually perfectly spherical butrather may by odd-shaped but would be considered generally “round” byone of skill in the art. The nanoparticle may be constructed of one ormore biocompatible substances and may be porous so as to permit elutionof a therapeutic substance embedded in it or may be biodegradable suchthat as it degrades the therapeutic substance is released into theenvironment.

A micelle is a spherical colloidal nanoparticle spontaneous formed bymany amphiphilic molecules in an aqueous medium when the CriticalMicelle Concentration (CMC) is exceeded. Amphiphilic molecules have twodistinct components, differing in their affinity for a solute, mostparticularly water. The part of the molecule that has an affinity forwater, a polar solute, is said to be hydrophilic. The part of themolecule that has an affinity for non-polar solutes such as hydrocarbonsis said to be hydrophobic. When amphiphilic molecules are placed inwater, the hydrophilic moiety seeks to interact with the water while thehydrophobic moiety seeks to avoid the water. To accomplish this, thehydrophilic moiety remains in the water while the hydrophobic moiety isheld above the surface of the water in the air or in a non-polar,non-miscible liquid floating on the water. The presence of this layer ofmolecules at the water's surface disrupts the cohesive energy at thesurface and lowers surface tension. Amphiphilic molecules that have thiseffect are known as “surfactants.” Only so many surfactant molecules canalign as just described at the water/air or water/hydrocarbon interface.When the interface becomes so crowded with surfactant molecules that nomore can fit in, i.e., when the CMC is reached, any remaining surfactantmolecules will form into spheres with the hydrophilic ends of themolecules facing out, that is, in contact with the water forming themicelle corona and with the hydrophobic “tails” facing toward the centerof the of the sphere. Therapeutic agents suspended in the aqueous mediumcan be entrapped and solubilized in the hydrophobic center of micelleswhich can result in an increase in the bioavailability as well asimproving the stability in biological surroundings, improving thepharmacokinetics and possibly decreasing the toxicity of the therapeuticagent. In addition because of their nanoscale size, generally from about5 nm to about 50 nm, micelles have been shown to exhibit spontaneousaccumulation in pathological areas with leaky vasculature and impairedlymphatic drainage, a phenomenon known as the Enhanced Permeability andRetention or EPR effect.

The problem with micelles formed from relatively low molecular weightsurfactants is that their CMC is usually quite high so that the formedmicelles dissociate rather rapidly upon dilution, i.e., the surfactantmolecules dissolve, and the concentration of micelles drops with theresulting precipitation of the therapeutic agent. Fortunately, thisshort-coming can be avoided by using lipids with a long fatty acid chainor two fatty acid chains, specifically phospholipids and sphingolipids,or polymers, specifically block copolymers to form the micelles.

Polymeric micelles have been prepared that exhibit CMCs as low as 10⁻⁶ M(molar). Thus, they tend to be very stable while at the same timeshowing the same beneficial characteristics as surfactant micelles.Since micelles are nano-scale particles, they may be administered usingthe porous balloon discussed above as well as in polymeric matrices.Examples of micelle-forming polymers are, without limitation, methoxypoly(ethylene glycol)-b-poly(ε-caprolactone), conjugates ofpoly(ethylene glycol) with phosphatidylethanolamine, poly(ethyleneglycol)-b-polyesters, poly(ethylene glycol)-b-poly(L-aminoacids),poly(N-vinylpyrrolidone)-bl-poly(orthoesters), poly(N-vinylpyrrolidone)-b-polyanhydrides and poly(N-vinylpyrrolidone)-b-poly(alkylacrylates).

In addition to the classical spherical micelles described above,therapeutic agents may be delivered using the methods of this inventionin compositions comprising synthetic worm micelles. Worm micelles, asthe name suggests, are cylindrical in shape rather than spherical. Theyare prepared by varying the weight fraction of the hydrophilic polymerblock to the total block copolymer molecular weight in the hydrophilicpolymer-b-hydrophobic polymer structure discussed above for preparingspherical micelles. Worm micelles have the potential advantage of notonly being bio-inert and stable as are spherical polymeric micelles butalso of being flexible. Polyethylene oxide has been used extensively tocreate worm micelles with a number of hydrophobic polymers such as,without limitation, poly(lactic acid), poly(ε-caprolactone),poly(ethylethylene) and poly(butadiene). A representative description ofworm micelle formation, characterization and drug loading can be foundin Kim, Y., et al., Nanotechnology, 2005, 16:S484-S491. The techniquesdescribed there as well as any other that is currently known or maybecome known in the future may be used in the regional delivery methodof this invention.

Somewhat more complex than micelles but likewise useful in the method ofthis invention are liposomes, particles comprised of a phospholipidbilayer that encloses an air-filled or hydrophilic liquid core.

Phospholipids are molecules that have two primary regions, a hydrophilichead region comprised of a phosphate of an organic molecule and one ormore hydrophobic fatty acid tails. In particular, naturally-occurringphospholipids have a hydrophilic region comprised of choline, glyceroland a phosphate and two hydrophobic regions comprised of fatty acid.When phospholipids are placed in an aqueous environment, the hydrophilicheads come together in a linear configuration with their hydrophobictails aligned essentially parallel to one another. A second line ofmolecules then aligns tail-to-tail with the first line as thehydrophobic tails attempt to avoid the aqueous environment. To achievemaximum avoidance of contact with the aqueous environment, i.e., at theedges of the bilayers, while at the same time minimizing the surfacearea to volume ratio and thereby achieve a minimal energy conformation,the two lines of phospholipids, know as a phospholipid bilayer or alamella, converge into a sphere and in doing so entrap some of theaqueous medium, and whatever may be dissolved or suspended in it, in thecore of the sphere. Examples of phospholipids that may be used to createliposomes are, without limitation,1,2-dimyristroyl-sn-glycero-3-phosphocholine,1,2-dilauroyl-sn-glycero-3-phosphocholine,1,2-distearoyl-sn-glycero-3-phosphocholine,1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine,1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine,1,2-dioleoyl-sn-glycero-3-phosphate monosodium salt,1,2-dipalmitoyl-sn-glycero-3-[phosphor-rac-(1-glycerol)] sodium salt,1,2-dimyristoyl-sn-glycero-3-[phospho-L-serine] sodium salt,1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-glutaryl sodium salt and1,1′,2,2′-tetramyristoyl cardiolipin ammonium salt.

Liposomes may be unilamellar, composed of a single bilayer, or they maybe multilamellar, composed of two or more concentric bilayers. Liposomesrange from about 20-100 nm diameter for small unilamellar vesicles(SUVs), about 100-5000 nm for large multilamellar vesicles andultimately to about 100 microns for giant multilamellar vesicles (GMVs).LMVs form spontaneously upon hydration with agitation of dry lipidfilms/cakes which are generally formed by dissolving a lipid in anorganic solvent, coating a vessel wall with the solution and evaporatingthe solvent. Energy is then applied to convert the LMVs to SUVs, LUVs,etc. The energy can be in the form of, without limitation, sonication,high pressure, elevated temperatures and extrusion to provide smallersingle and multi-lamellar vesicles. During this process some of theaqueous medium is entrapped in the vesicle. Generally, however, thefraction of total solute and therefore the amount of therapeutic agententrapped tends to be rather low, typically in the range of a fewpercent. Recently, however, liposome preparation by emulsion templating(Pautot, et al., Langmuir, 2003, 19:2870) has been shown to result inthe entrapment of virtually 100% of aqueous solute. Emulsion templatingcomprises, in brief, the preparation of a water-in-oil emulsionstabilized by a lipid, layering of the emulsion onto an aqueous phase,centrifugation of the water/oil droplets into the water phase andremoval of the oil phase to give a dispersion of unilamellar liposomes.This method can be used to make asymmetric liposomes in which the innerand outer monolayers of the single bilayer contain different lipids.Liposomes comprising phospho- and/or sphingolipids may be used todeliver hydrophilic (water-soluble) or precipitated therapeuticcompounds encapsulated within the inner liposomal volume and/or todeliver hydrophobic therapeutic agents dispersed within the hydrophobiccore of the bilayer membrane.

It has been reported that large unilamellar liposomes alone, that is,absent of any additional therapeutic agent, when administered in largeamounts intravenously may stimulate reverse cholesterol transport andmay have anti-atherogenic effects similar to that of HDL. Williams, K.J., et al., Arterioscler. Thromb. Vasc. Biol., 2000, 20:1033-39. Whilefurther evaluation is necessary, if such is proven to be the case,administration of large liposomes without added therapeutic agent usingthe delivery interface of this invention may provide a beneficial effecton patients known or suspected to be afflicted with a vascular disease.

The diblock copolymers discussed above with regard to micelle formationcan be further modified to form bilayer structures similar to liposomes.The structures are referred to as polymersomes. Depending on the lengthand chemical nature of the polymers in the diblock copolymer,polymersomes can be substantially more robust that liposomes. Inaddition, the ability to control completely the chemical nature of eachblock of the diblock copolymer permits tuning of the polymersome'scomposition to fit the desired application. For example, membranethickness can be controlled by varying the degree of polymerization ofthe individual blocks. Adjusting the glass transition temperatures ofthe blocks will affect the fluidity and therefore the permeability ofthe membrane. Even the mechanism of release can be modified by alteringthe nature of the polymers.

Polymersomes can be prepared in the same manner as liposomes. That is, afilm of the diblock copolymer can be formed by dissolving the copolymerin an organic solvent, applying a film of the copolymer-containingsolvent to a vessel surface, removing the solvent to leave a film of thecopolymer and then hydrating the film. This procedure, however, tends toresult in a polydisperse population of micelles, worm micelles andvesicles of varying sizes. Polymersomes can also be prepared bydissolving the diblock copolymer in a solvent and then adding a poorsolvent for one of the blocks, which will result in the spontaneousformation of polymersomes.

As with liposomes, polymersomes can be used to encapsulate therapeuticagents by including the therapeutic agent in the water used to rehydratethe copolymer film. Polymersomes can also be force-loaded by osmoticallydriving the therapeutic agent into the core of the vesicle. Also as withliposomes, the loading efficiency is generally low. Recently, however, atechnique has been reported that provides polymersomes of relativemonodispersivity and high loading efficiency; (generation ofpolymersomes from double emulsions. Lorenceau, et al., Langmuir, 2005,21:9183-86). (is this the cite?) The technique involves the use ofmicrofluidic technology to generate double emulsions consisting of waterdroplets surrounded by a layer of organic solvent. Thesedroplet-in-a-drop structures are then dispersed in a continuous waterphase. The diblock copolymer is dissolved in the organic solvent andself-assembles into proto-polymersomes on the concentric interfaces ofthe double emulsion. The actual polymersomes are formed by completelyevaporating the organic solvent from the shell. By this procedure thesize of the polymersomes can be finely controlled and, in addition, theability to maintain complete separation of the internal fluids from theexternal fluid throughout the process allows extremely efficientencapsulation.

When it is stated that a permeability-enhancing composition“independently comprises a separate” particulate carrier from thatcomprising a therapeutic agent, what is meant is that thepermeability-enhancing composition not only is encapsulated in aseparate particulate carrier but that carrier may be different from thatcontaining the therapeutic agent. For example, without limitation, thetherapeutic agent may be encapsulated in a liposome while thepermeability-enhancing composition may be encapsulated within, oradhered to the surface of, a nanoparticle, a micelle, a worm micelle ora polymersome.

As used herein, a “targeting component” refers to a molecular entitythat has a particular affinity for another molecular entity such that ifthe second entity is present at a locale of interest, the first entity,when it encounters the second entity, will interact with the secondentity and thereupon be immobilized at the locale. An example oftargeting is the affinity of an antibody for an antigen. If a particularantigen is responsible for the diseased condition of a locale ofinterest and therefore is present at the locale, it would be possible tobind a therapeutic agent or a particular carrier to an antibody to thatantigen in such a manner that the binding affinity of the antibody forthe antigen is not affected and then to administer the carrier antibodyto the patient. When the antibody encounters the antigen, it will bindto the antigen and be immobilized. The therapeutic agent can theninteract with the antigen. Another example of targeting is the affinityof a ligand for a receptor expressed on a cell's surface. If thereceptor is unique to the locale of interest due, for instance, to itsrelationship to the disease at the locale, a highly localized, diseasespecific treatment may be possible. Specific examples of such targetingentities include, without limitation, are antibodies to CD34, RGD,YIGSR, peptides and antibodies to IIbIIIa, heparin, hyaluronic acid,laminin, collagen, ICAM-1, ICAM-2, ICAM-3, fibrinogen, fibronectin,vitronectin, thrombospondin, osteopontin, integrins, VCAM-1, N-CAM,PECAM-1, IgCAM, folate, oligonucleotide aptamers, selectins, andcadherins. Other targeting entities will be apparent to those skilled inthe art based on this disclosure; all such targeting entities are withinthe scope of this invention.

Nitric oxide (chemical formula NO) is a gaseous signaling molecule thatplays a role in a host of biological processes. Also known as“endothelium-derived relaxing factor,” NO is used by the endotheliumlining of blood vessels to signal surrounding smooth muscle cells torelax, causing the vessel to dilate. As a result of this dilation, thecells of the endothelium are pulled away from one another and the EMbetween the cells is stretched and rendered more permeable. Thus NO maybe used to accomplish an objective of this invention, enhancedpermeation of the endothelium.

As used herein, a “nitric oxide generator” refers to a molecule thatunder physiological conditions releases NO. Examples of in vivo NOgenerators include, without limitation, S-nitrosocysteine,S-nitroso-N-acetylpenicillamine and sodium nitroprusside.

As used herein, a “mechanical permeation enhancer” refers to a devicethat when operationally directed to the endothelium at the locale ofinterest causes an increase in the permeability of the endothelium atthat site. Examples of mechanical permeation enhancing means include,without limitation, phonophoresis, sonophoresis, low intensity pulsedultrasound stimulation (LIPUS), iontophoresis and pressure pulsegeneration.

While the current invention has been described with regard to certainembodiments it is understood that those skilled in the art will, basedon this disclosure, be able to devise, without undue experimentation,other embodiments not expressly set forth herein. All such embodimentsare nevertheless within the scope of this invention.

What is claimed:
 1. A method of treating a vascular disease, comprising:providing an implantable medical device; advancing the implantablemedical device to a locale of interest in a vessel of a patient;administering a permeability-enhancing composition from the implantablemedical device to the locale of interest, wherein: thepermeability-enhancing composition physiochemically interacts with atleast one component of endothelial cells or extracellular matrix; and atherapeutic agent is administered as a component of thepermeability-enhancing composition or concomitantly with but separatelyfrom the permeability-enhancing composition.
 2. The method of claim 1,wherein the permeability-enhancing composition comprises a saponin, asemi-synthetic saponin, DS-1, DS-1(R), DS-2 or QH-957.
 3. The method ofclaim 1, wherein the permeability-enhancing composition compriseshyaluronidase, recombinant hyaluronidase or rHuPH2O.
 4. The method ofclaim 1, wherein the implantable medical device comprises a stent. 5.The method of claim 1, wherein the therapeutic agent comprises aparticulate carrier.
 6. The method of claim 5, wherein the particulatecarrier comprises a nanoparticle, a micelle, a worm micelle, a liposomeor a polymersome.
 7. The method of claim 6, wherein the nanoparticle,micelle, worm micelle, liposome or polymersome further comprises thepermeability-enhancing composition.
 8. The method of claim 7, whereinthe permeability enhancing composition independently comprises aseparate particulate carrier from that the therapeutic agent comprises,the particulate carrier being independently selected from the groupconsisting of a nanoparticle, a micelle, a worm micelle, a liposome or apolymersome.
 9. The method of claim 6, wherein the nanoparticle,micelle, worm micelle, liposome or polymersome further comprises atargeting component disposed on its surface and, further, thepermeability-enhancing composition is likewise disposed on its surface.10. The method of claim 9, wherein the nanoparticle, micelle, wormmicelle, liposome or polymersome further comprises a targeting componentdisposed on its surface and, further, the permeability-enhancingcomposition is likewise disposed on its surface.
 11. The method of claim1, wherein the locale of interest comprises an atherosclerotic lesion, arestenotic lesion, a suspected vulnerable plaque, a vulnerable plaque ora peripheral arterial lesion.